Rolleston said: "He pushed the boys to her and she got them but she couldn't grab him. The sea just took him."
Police, the Trustpower TECT Rescue Helicopter and Tauranga Coastguard launched a search for Apaapa.
His body was found in Tauranga Harbour about 1 hours after the search began.
Apaapa was a strong swimmer who may have become exhausted while helping the children. But the family were still stunned that he could drown at a beach where he had been swimming all his life.
Apaapa's brother Nick said he had been collecting shellfish at the beach since he was a child. "We knew that beach like the palm of our hands," he said.
Apaapa, who had six siblings, was known for his gentleness and helpful nature, said Nick.
"He and Kahui always helped a lot of people. Even though I am the older brother he was always there for me."
Apaapa's eldest son Justin, his partner and their newborn baby - his first grandchild - also witnessed the tragedy.
His daughter Grace is travelling from Perth as the family gather for his tangi at the family marae.